I love paint apps, and in particular use the hell out of MSPaint (I realize this is based on MacPaint), so I was really excited for this. I think it's fair to say I'm specifically the target audience!
....But I agree that the $20 pricetag is insulting. Especially considering that this is a version 0.2 early release that even declares it makes no guarantees to finish/implement missing features.
I think a substantially higher number of people would be willing to purchase this at a more reasonable $5.